Multi-stage in-well aerator

Abstract

An in-well system for simultaneously treating and extracting groundwater by injecting compressed gas through the groundwater in multiple successive stages as it is pumped out of a well. The process is usable for in-well aeration stripping of Volatile Organic Compounds from groundwater or for other applications in which it is desirable to pass compressed gas through groundwater to alter the physical, chemical, or radiological properties of the groundwater prior to its discharge from the well.

What is claimed as new and desired to be protected by patent is set forth in the appended claims: 
     
       1. A system for treating groundwater including a means for directing water flow by gravity along multiple separate paths within a water well during the pumping process and a means for injecting compressed gas into the water at separate locations within each of the multiple separate paths and a means for transporting the injected gas to the top of the water well for collection or dispersion into the atmosphere after it has passed through the water, and a means for discharging the water at the top of the well after it has been treated, wherein said means for directing water flow by gravity along multiple separate paths within a water well during pumping, said well having a minimum water level and a maximum static water level, includes: one or more pipes mounted concentrically within a lower section of a well casing below the minimum water level within the well during pumping and sealed at the bottom of the well but allowing alternating upward and downward flow of water by gravity from one annular space to another commencing with an upward flow within an outermost annular space and ending with a downward flow to a pumping inlet at the bottom of the well within an innermost annular space;   one or more pipes mounted concentrically within an upper section of the well casing above the maximum static water level within the well which allows alternating upward and downward flow of water by gravity from one annular space to another commencing with a downward flow within an innermost annular space and ending with an upward flow to a discharge outlet at the top of the well within an outermost annular space and a means for supporting the pipes at their bottom and separating them from the well below; and   surge tanks mounted upon the tops of the concentric pipes mounted above the maximum static water level to prevent water flow during hydraulic surges.   
     
     
       2. The system of claim 1 wherein said means for injecting compressed gas into the water at separate locations within each of the multiple separate paths includes: a compressed gas source comprising an air compressor or compressed gas tanks;   valves, pressure gauges, and gas flow meters for controlling the pressure and flow rate of the compressed gas;   one or more compressed gas admixture sources comprising compressed gas tanks;   valves, pressure gauges, and gas flow meters for controlling the pressure and flow rate of compressed gas admixtures into main compressed gas lines;   separate compressed gas lines for transporting compressed gas and compressed gas admixtures to separate injection points within each annular space in both the upper and lower well sections;   gas injection assemblies for injecting the gas into the water within each annular space in both the upper and lower well sections.   
     
     
       3. The system of claim 1 wherein said means for transporting the injected gas to the top of the water well for collection or dispersion into the atmosphere after it has passed through the water includes: one or more vent tubes passing from the lower well section through a plug assembly and to the top of the well which may be vented to the atmosphere or fitted with collection devices to transport the gas to other equipment for treatment;   one or more surge tanks affixed to the top of the concentric pipes in the upper section of the well which may be fitted with caps to collect gas moving out of the water in the upper well section for transport to other equipment for treatment.   
     
     
       4. The system of claim 1 wherein said means for supporting the pipes mounted concentrically within the well casing above the maximum static water level within the well at their bottom and separating them from the well below includes: a horizontal watertight plug placed above the maximum static water level within the well and supported either by cables attached to the plug and land surface or supported by a vertical pipe extending from the bottom of the plug to the bottom of the well;   a means for allowing vertical penetrations through the plug for the passage of compressed gas lines, vent tubes, and drain lines from above the plug to below the plug;   a means for draining water from the area above the plug to the area below the plug using a vent tube without obstructing the inside of the vent tube.   
     
     
       5. The system of claim 4 wherein said means for draining water from the area above the plug to the area below the plug using a vent tube without obstructing the inside of the vent tube includes: a standard PVC pipe sliding slip style repair coupling mounted vertically in line with the vent tube and just above the upper surface of the plug in which holes are drilled into the body of the repair coupling between the limits of travel of the internal plunger, thus allowing water to pass from the outside of the fitting to within the center of the fitting if the plunger is raised, or to prevent such passage of water if the plunger is lowered.